Type or tap your chords and this free chord progression analyzer tells you what key they are in, writes the Roman numeral of every chord, colours its function (tonic, predominant, dominant) and marks cadences, secondary dominants, borrowed chords and famous progressions. You can also enter Roman numerals such as I V vi IV in G, get ideas for the next chord, transpose, find a capo position and hear the progression.
Chord Progression Analyzer
Type or tap chords (or Roman numerals) to get the key, Roman numeral analysis, chord functions, cadences and the next chord.
Separate chords with spaces: C G Am F · F#m7 · Bbmaj7 · G/B · Dm7b5. Roman numerals work too: ii7 V7 Imaj7 in Bb.
Colour chords: secondary dominants, borrowed chords, Neapolitan
What the analysis found
Next chord
Suggestions in the same key, most common first. Tap one to add it and hear it.
Transpose and capo
Everything runs in your browser: nothing is uploaded or recorded. Turn up the volume to hear the chords.
Related Tools
- Chord Progression Finder
Find the chords of a song from audio or your microphone.
- Scale Finder
See which scales fit your chords: the notes to improvise with.
- Song Key Finder
Get the key of a recording straight from the audio.
- Interval Ear Training
Train your ear to hear the steps between chord roots.
- Online Metronome
Practise your progression in time.
- Pitch Detector
See the exact note you sing or play, live.
How to Analyze a Chord Progression
- Enter the chords. Type them with spaces, commas or bars: C G Am F, Dm7 G7 Cmaj7, F#m7b5 B7 Em. Sharps and flats can be typed as # and b. Slash chords (C/E), sus, add9, 6, 9, 11, 13, dim, ø and aug chords are understood. Or press Tap chords and tap the chords of any key.
- Read the key. The most likely key comes with a confidence score and the alternatives. Tap an alternative, or choose a key in the menu, to see the numerals in that key.
- Read the analysis sheet. Under each chord you see its Roman numeral and its function colour. Cadences and named progressions are marked on the sheet and listed under What the analysis found.
- Tap any chord for its notes, formula, an explanation of why it has that numeral, a piano voicing and the chord in notation.
- Play, extend and share: play the progression with a loop and tempo, tap a next-chord suggestion, transpose it, or copy a link.
What Key Is This Chord Progression In?
To find the key of a chord progression, the analyzer tests all 24 major and minor keys and keeps the one that explains your chords best. It looks for the same clues a musician uses:
- Do all chords fit the key? C, G, Am and F all belong to C major, so C major and A minor are candidates.
- Which chord feels like home? Progressions usually start or end on the tonic chord.
- Is there a V–I? A dominant chord moving to its tonic (G7 to C) is the strongest proof of a key.
- Can the outside chords be explained? A secondary dominant or a borrowed chord fits a key; an unexplained chord counts against it.
C G Am F starts on C, so C major wins; Am F C G uses the same chords but starts on Am, so A minor is first and C major second. Relative keys share all their notes, so when the confidence is low, trust your ear: the chord where the song comes to rest is the tonic. More methods are in how to find the key of a song.
Roman Numeral Chord Calculator
Roman numerals name each chord by the scale degree of its root, so a progression can be compared in every key. Upper case means a major chord, lower case minor, ° diminished, ø half-diminished and + augmented. These are the chords of C major and A minor:
| Degree | C major | Function | A minor | Function |
|---|---|---|---|---|
| 1 | I · C (Cmaj7) | Tonic | i · Am (Am7) | Tonic |
| 2 | ii · Dm (Dm7) | Predominant | ii° · B° (Bø7) | Predominant |
| 3 | iii · Em (Em7) | Tonic | III · C (Cmaj7) | Tonic |
| 4 | IV · F (Fmaj7) | Predominant | iv · Dm (Dm7) | Predominant |
| 5 | V · G (G7) | Dominant | V · E (E7), or v · Em | Dominant |
| 6 | vi · Am (Am7) | Tonic | VI · F (Fmaj7) | Predominant |
| 7 | vii° · B° (Bø7) | Dominant | VII · G (G7), vii° · G♯° | Dominant |
Minor keys usually raise the 7th note, which turns v into a major V (E or E7 in A minor) and gives the leading-tone chord vii°. Inversions get figures: C/E is I6, C/G is I6/4, G7/B is V6/5, G7/D is V4/3 and G7/F is V4/2. When you type Roman numerals, I7 and IV7 follow the classical rule (Cmaj7, Fmaj7 in C); to get blues-style dominant 7ths, type chord names such as C7 F7 G7.
Tonic, Predominant and Dominant
Each chord of the sheet has a colour and a code. T (green) chords sound stable: I, and vi and iii, which share two notes with I. PD (amber) chords such as ii and IV lead away from home. D (red) chords such as V and vii° create tension that wants to resolve to I. Most music moves T → PD → D → T, and seeing the colours makes that motion visible. Secondary dominants are violet (D→ii means “dominant of ii”) and unexplained chromatic chords are grey.
Secondary Dominants, Borrowed and Chromatic Chords
Chords outside the key are not mistakes. The analyzer works as a secondary dominant calculator: a major or 7th chord a fifth above a chord of the key is its dominant, written V/x. It also names borrowed chords (modal mixture), the Neapolitan and augmented sixth chords.
| Chord in C major | Analysis | Why |
|---|---|---|
| A7 → Dm | V7/ii | Dominant of Dm; C♯ leads up to D |
| D or D7 → G | V/V, V7/V | Dominant of the dominant; F♯ leads to G |
| E7 → Am | V7/vi | Dominant of the relative minor |
| F♯dim7 → G | vii°7/V | Leading-tone chord of G |
| Fm | iv (borrowed) | From C minor: the bittersweet minor iv |
| B♭, A♭ | ♭VII, ♭VI (borrowed) | From C minor; ♭VII is the rock “Mixolydian” chord |
| D♭ → G | N (Neapolitan) | Major chord on ♭II, leads to V |
| A♭7 → G | Ger+6 | German augmented sixth resolving to V |
| D♭7 → C | subV7 | Tritone substitute for G7 |
If you type an unusual spelling such as D♯ in C major, the chord is shown as E♭ with a “typed D♯” note, so the chord tones are spelled correctly for the key. Scales and modes behind borrowed chords are explained in all types of music scales.
Cadences and Famous Progressions
A cadence is the harmonic punctuation at the end of a phrase. The analyzer marks authentic (V–I), plagal (IV–I, including the minor plagal iv–I), half (ending on V), deceptive (V–vi) and Phrygian (iv6–V in minor) cadences, plus backdoor and tritone-substitute resolutions. It also recognizes well-known patterns:
| Progression | Roman numerals | In C major / A minor |
|---|---|---|
| Axis (four-chord pop) | I–V–vi–IV | C G Am F |
| 50s / doo-wop | I–vi–IV–V | C Am F G |
| Jazz ii–V–I | ii7–V7–Imaj7 | Dm7 G7 Cmaj7 |
| 12-bar blues | I7–IV7–I7–V7… | C7 F7 C7 G7… |
| Pachelbel’s Canon | I–V–vi–iii–IV–I–IV–V | C G Am Em F C F G |
| Andalusian cadence | i–VII–VI–V | Am G F E |
| Epic minor loop | i–VI–III–VII | Am F C G |
| Aeolian cadence | ♭VI–♭VII–I | A♭ B♭ C |
Next Chord Finder
Stuck after a chord? The next chord panel lists what usually follows the last chord in your key, most common first: after V it suggests I, then vi for a deceptive surprise; after a secondary dominant it suggests the chord it points to. If most of your chords are 7th chords, the suggestions are too. Tap one to add it and hear how it sounds. Recognizing these moves by ear is a skill you can build with the ear training guide.
Transpose and Guitar Capo
Pick a new key and every chord is rewritten with correct sharps or flats while the Roman numerals stay the same; Use these chords loads them into the analyzer. For guitar, the capo menu shows the shapes to play on each fret and marks the easiest option: E♭ A♭ B♭ becomes D G A with the capo on fret 1. Tune up first with the guitar tuner. To change the key of an audio recording instead, use the pitch shifter.
Frequently Asked Questions
Can it find the chords of a song?
No, this page analyzes chords you type or tap. To detect chords from audio or your microphone, use the Chord Progression Finder in Related Tools, then paste the chords here.
Is the key detection always right?
For most pop, rock, folk and jazz progressions, yes. Short or modal progressions can fit several keys; the confidence score and alternatives show when that happens.
Does it work for minor keys and modes?
Yes. It uses natural, harmonic and melodic minor, and names Mixolydian and Dorian colours when ♭VII or a major IV appear.
Is anything uploaded?
No. The analysis and the sound run in your browser.